1. Field of the Invention
The present invention relates to an auxiliary safety lift device, and more particularly to an auxiliary safety lift device for an elevator.
2. Description of the Related Art
A conventional safety device for an elevator in accordance with the prior art shown in FIG. 1 comprises a brake 12 secured on one side of the main motor 11 of the elevator. When the electric power of the elevator is cutoff or when the control system of the elevator fails, the brake 12 will detect the cutoff of the electric power and will automatically lock the differential 13 and the cable 14 of the elevator, thereby preventing the elevator from falling down.
The conventional safety device also comprises a press button which is connected to that of the alarm bell of the guard of the building so that when a person is in the cab of the elevator, the user may inform the guard of the accident.
However, when the elevator is stopped, the user in the cab of the elevator cannot assure the height and position of the elevator so that he cannot escape from the elevator by himself and has to stay in the cab of the elevator and wait continuously until the rescuer arrives. In such a manner, when the fire, the earthquake or the like takes place, the user limited in the cab of the elevator is easily hurt due to the accident.
In addition, when the control system of the elevator fails, the brake 12 of the conventional safety device will automatically lock the elevator for preventing the elevator from falling down so that the elevator easily stops between two adjacent floors.
However, the user limited in the cab of the elevator cannot control the position of the elevator by himself. Therefore, when the rescuer opens the door of the elevator, the user has to climb upward or downward from the elevator through a certain distance so as to reach the opening of the nearest floor, thereby easily causing danger to the user.
The present invention has arisen to mitigate and/or obviate the disadvantage of the conventional safety device for an elevator.
In accordance with one aspect of the present invention, there is provided a auxiliary safety lift device for an elevator comprising: a main elevator power system; a spare electric power system having an independent power supply; a secondary motor connected with and operated by the spare electric power system; a secondary speed reducer driven by the secondary motor; and an electromagnetic clutch.
The main elevator power system includes a main motor having a main shaft, an electromagnetic brake, and a main speed reducer.
The electromagnetic clutch includes an electromagnetic disk secured on the main motor of the main elevator power system, and connected with and driven by the spare electric power system; a transmission disk rotatably mounted on the electromagnetic disk and secured to the main shaft of the main motor of the main elevator power system for rotating the main shaft; a drive disk rotatably mounted on the secondary speed reducer and rotated by the secondary speed reducer; and a spring sheet secured on the drive disk and located adjacent to the transmission disk.
In such a manner, when the electromagnetic disk is energized by the spare electric system, the spring sheet is attracted by the electromagnetic disk to engage the transmission disk so that the transmission disk is rotated with the drive disk so as to rotate the main shaft of the main motor of the main elevator power system.
Accordingly, when the power of the main elevator power system is cutoff, the spare electric power system is started to drive the secondary motor to drive the secondary speed reducer which in turn co-operates with the electromagnetic clutch to rotate the main shaft of the main motor of the main elevator power system to drive the main speed reducer of the main elevator system for lifting the elevator.
Preferably, the auxiliary safety lift device also comprises a control system connected with the spare electric power system for controlling it.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.